There exists a need for applying an identifying "signature" to wireless audio transmissions, In commercial radio, for revenues are raised by a station broadcaster by the acceptance for broadcast of paid programming. Typically, such paid programming is in the form of commercials or advertisements, but revenues may also be generated by the broadcast of paid political announcements, quasi "public interest" transmissions and the like. The consideration paid by the advertiser or its agent, such as an advertising agency, is a function of both the length of the advertising "spot" to be aired and the potential audience reachable by the station at the time of intended broadcast. It is obviously the concern of the advertiser that it receive a proper return on its investment; that is, that the station broadcast a signal which bears the entirety of its programming at the agreed-upon time and in the proper rotation of commercials ordered.
The major radio broadcast networks alone have some 5700 local affiliate stations. Each station has the ability to broadcast local advertising spots, as well as spots provided by the network. Any practical system for monitoring air time must be capable of identifying both the originator of the spot and the station over which it is transmitted.
While the number of listeners tuned to a station is beyond the direct control of the broadcaster, the broadcaster does have direct control over the condition of the signal it transmits. Among the advertiser's concerns which are within the broadcaster's control are the quality of the audio signal bearing the commercial, and the airing of the entirety of the spot at the proper time and in the proper order.
It is vitally important to the advertiser that the entirety of its spot be transmitted. As commercials are often prepared with the "tag" or "punch" at the end of the spot, it is important that the commercial does not end prematurely. If, for example, a 60-second spot is only broadcast for 55 seconds, shortening of air time due to loss occurring at the beginning of the spot is of less concern than loss at the end. Thus, while any time loss is meaningful, the position of such loss within the commercial is determinative of the loss of value resulting therefrom.
While it has been a standard industry practice for stations to maintain logs of the content of their broadcasts, the log is unable to document the specific identity, quality or precise length of a broadcast segment. In addition, because the logs are maintained by station personnel themselves, there exists the possibility that inaccurate or erroneous information can be transcribed. Third-party services also make off-the-air recordings of station broadcasts, and compile reports based upon review of the recordings. This is a time consuming process, however, as the actual analysis of the tape is performed by a human listener. The monitoring of a large number of broadcasts over a significant length of time is both costly and inefficient.
Another methodology employed to confirm the existence of the airing of a particular spot is to directly compare a recording of the audio track broadcast to a reference recording of the same material. Due to normal degradation of the signal upon broadcast, coupled with static and other atmospheric disturbances, however, such comparison is of only limited reliability. An audio "signature" or "fingerprint" of a portion of an audio segment can be utilized for comparison purposes, but the comparison requires significant analysis. It is believed that such routines are no more than 85% accurate.
It is accordingly a purpose of the present invention to provide a new and improved method and apparatus for the identification and monitoring of a wireless audio broadcast.
Another purpose of the present invention is to provide a new and improved method and apparatus by which audio program identification can be accomplished in an undetectable manner.
Still another purpose of the present invention is to provide such a method and apparatus which does not degrade the audio signal.
Still another purpose of the present invention is to provide such a method and apparatus which permits both source and signal identification and duration data to be determined.
Yet a further purpose of the present invention is to provide such a method and apparatus which may be incorporated into conventional broadcast systems and which may be implemented simply and reliably.